Delete using native query

DrRakha

Delete using native query , the following example is supposed to delete a topic record using its id .Notice that native query use actual physical names of database . For example TOPIC (Database table name ) instead of Topic (Name of the entity class ) .

Code:

package com.codemiles.jpa;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;

/**
 * @author codemiles.
 *
 */
public abstract class JPAService {
    private EntityManager entityManager;

    /**
     * @param args
     */
    public void deleteTopic(Topic topic) {
    EntityManagerFactory factory = Persistence
            .createEntityManagerFactory("persistenceUnitName");
    entityManager = factory.createEntityManager();
    entityManager.getTransaction().begin();
    deleteTopicById(topic.getId());
    entityManager.getTransaction().commit();
    entityManager.close();
    factory.close();

    }
 
 
    /**
     * @param id 
     *  
     * @return
     *   number of affected columns . 
     */
    public int deleteTopicById(int id){
    Query query = entityManager.createNativeQuery("Delete from TOPIC where ID=?");
    query.setParameter(1, id);
    return query.executeUpdate();
    
    }

}

 

entity class :

Code:

package com.codemiles.jpa;
import java.util.Collection;
import java.util.Date;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;



@Entity
@Table(name="TOPIC")
public class Topic implements java.io.Serializable{
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    @Id
    private int Id;
    private String title;
    private Date creationDate;
    private Date modifedDate;
    private String content;
    @OneToMany(mappedBy="topic")
    private Collection<Comment> comments;

    public int getId() {
        return Id;
    }
    public void setId(int id) {
        Id = id;
    }
    
    @Column(name="TITLE")
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    
    @Column(name="CREATION_DATE")
    public Date getCreationDate() {
        return creationDate;
    }
    public void setCreationDate(Date creationDate) {
        this.creationDate = creationDate;
    }
    
    @Column(name="MODIFED_DATE")
    public Date getModifedDate() {
        return modifedDate;
    }
    public void setModifedDate(Date modifedDate) {
        this.modifedDate = modifedDate;
    }
    
    @Column(name="CONTENT")
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    public void setComments(Collection<Comment> comments) {
    this.comments = comments;
    }
    public Collection<Comment> getComments() {
    return comments;
    }
}
 

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Delete using native query